Most automobiles are presently powered by an internal combustion engine which must be spun up to speed externally before they can operate. The engines are usually spun up to speed by an electric motor that is powered by a battery. The battery is then charged by a generator connected to the engine once the engine is operating or running. The battery is usually able to store enough charge for the periods that the engine is not running in order to start the engine when needed.
When the battery does not have sufficient charge to start the engine, a way must be found to recharge the battery or bypass the battery with a separate charge. Since very often a discharged battery is caused by an external drain such as leaving the lights on or playing the radio, once the engine is started by either recharging the battery or bypassing it by sending a separate charge the automobile will continue to operate properly.
Since there are many things that will temporally cause a battery to lose its charge, the need to recharge or bypass batteries with separate charges is common. Very often another or booster battery is brought to the vicinity of the dead battery and electrical cables are used to connect the booster battery to the dead battery in parallel in order to recharge and/or bypass the dead battery. This often known as boosting or jump starting the dead battery or engine.
In this method of boosting, the cables are disconnected from the batteries after each use so as to prevent short circuits. This method and structure however, is cumbersome since there are at least two parts and they demand great attention since there are 4 connections to make and a bad connection in either one will result in a short circuit or failure to start the engine.
Some manufacturers have tried to resolve the problem by combining the battery and cables in one unit. The problems that have arisen with these units are that the cables which are permanently connected to the battery are always live so they have to be protected as to not touch each other. The amount of amperage available in these batteries is very large and if the cables touch each other it would create a short circuit and damage the cables and batteries. To isolate the live cables, some manufacturers have used protective pouches. These are not practical to use since they are often in the way when trying to boost. Also it is time consuming to put the cables in and out of the pouches.
Other manufacturers have incorporated a male cigar lighter plug at the end of the cables permitting the user to plug this into the female cigar lighter plug of the vehicle. The problem with this unit is that one can only use this tool on vehicles equipped with female cigar lighter plugs. Also, since the plugs almost always have a maximum amperage rating of 30 amps and that most starter motors draw much more than 30 amps., the capacity is not adequate.